1. Technical Field of the Invention
The present invention relates in general to the telecommunications field, and in particular, to a method and system for implementing a Network Access Server (NAS) in association with a telecommunications switch.
2. Description of Related Art
Access to the Internet is increasingly desirable to achieve economic, educational, and communicative purposes. Individuals typically access the Internet from a personal electronic device such as a computer, personal digital assistant, or cellular phone. Subscribers in a public telephone network establish data connections to the Internet over an NAS. The data connections to an NAS are established over Plain Old Telephone Service (POTS) phone lines or Integrated Services Digital Network (ISDN) lines. At the subscriber end, normal POTS modems or ISDN network terminals (NT-Is, or network terminals on an ISDN connection) are used to initiate the communications. Personal computers with suitable communications software and hardware are frequently used as the terminal in conjunction with either a modem or NT-I.
The NAS acts as a router and concentrator for Internet Protocol (IP) packets that arrive via the data connections. The link level of the incoming data connections can also be terminated at the NAS. For analog lines, such as those originating with a POTS modem, modem pools may be provided at the NAS. IP packets are forwarded to an Internet gateway through various possible channels from the NAS. The IP packets are then transported over the Internet to the appropriate Internet destination.
In summary, an NAS accepts modem or ISDN calls to an Internet service provider (ISP), terminates the phone connection, and interprets the link layer protocol, e.g., Point to Point Protocol (PPP). The IP data packets are then forwarded to the Internet or possibly an intranet.
An NAS typically has an internal network for receiving and routing packets to the Internet. The internal network includes both electronic devices and one or more edge routers (e.g., an Internet Point-of-Presence, or INET-POP) The electronic devices are important for terminating the phone line connection and reformatting a subscriber""s data to comport with the Internet protocol. In a conventional NAS, however, communication regarding resource availability is insufficient.
The electronic devices, for example, on the internal network can exhaust the supply of a given resource. Conventional electronic devices do not adequately convey such resource depletion to the logic responsible for routing incoming data communications to individual electronic devices. As a result, a subscriber""s call may be routed to an electronic device that has exhausted all available resources, which may be required for Internet access. Consequently, the subscriber""s attempt to access the Internet is abruptly truncated without explanation.
Such truncation is extremely annoying to the subscriber, who is unable to determine why the access attempt failed. The subscriber must redial and will (hopefully) be assigned an electronic device with adequate resources. Furthermore, this annoyance is exacerbated by customer-service concerns because the annoyance may cause the subscriber to cease attempting to access the Internet even when other electronic devices on the internal network have sufficient resources to facilitate Internet access.
In summary, conventional electronic devices and related apparatus do not (i) provide adequate information regarding resource availability to the routing logic in the NAS and associated telecommunications switch, or (ii) enable the routing logic to assign incoming calls only to electronic devices with sufficient resources for handling the incoming calls.
The present invention provides a method and apparatus for an NAS whereby resource depletion information is provided to call routing logic. The call routing logic is preferably software, hardware, firmware, or a combination thereof that attempts to provide communication throughput by directing incoming calls to a particular device of the NAS. As resources are depleted, the depletion(s) can be communicated to the call routing logic. Therefore, the call routing logic can avoid assigning incoming calls to devices with insufficient resources.
In a preferred embodiment, an NAS in association with a telecommunications switch includes a group of processing devices. The processing devices provide formatting changes for data being transmitted from the public telephone network to a private network such as the Internet, and vice versa. The processing devices are interconnected via an Ethernet network and include a router that is a gateway to the Internet.
Resource depletion messages are received at call routing logic from each processing device on the Ethernet network as resources are depleted. For example, if an IP address pool for a particular ISP is exhausted, a message so indicating is transmitted. Incoming calls can be routed away from the processing device with the depleted resource to ensure that public telephone network subscribers gain access to the Internet. When a resource is replenished, either by adding new resources or recapturing previously assigned resources, this information may also be forwarded to the call routing logic so that incoming calls may again be routed to the relevant processing device.
An important technical advantage of the present invention is that processing devices can send messages regarding resource depletion to call routing logic.
Another important technical advantage of the present invention is that call routing logic is enabled to assign incoming calls only to processing devices with sufficient resources to handle the incoming call.
Yet another important technical advantage of the present invention is that an NAS can prevent dial up subscribers from detecting resource depletion problems by routing their calls only to the devices with adequate resources.
Yet another important technical advantage of the present invention is that depletion of an IP address pool for an individual ISP is recognized and considered when making call routing decisions.
The above-described and other features of the present invention are explained in detail hereinafter with reference to the illustrative examples shown in the accompanying drawings. Those skilled in the art will appreciate that the described embodiments are provided for purposes of illustration and understanding and that numerous equivalent embodiments are contemplated herein.